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Honda Grom Bike Vs Kawasaki Z125: Specs, Speed And Price

Chaparral Motorsports
January 14, 2019
Last Updated: May 28, 2020

When it comes to mini-bikes, Honda has almost always been top dog. However, in 2017, a few years after the Honda Grom made a big splash in the small displacement motorcycle market, Kawasaki followed up with their own contender: the Z125 Pro. Both bikes share a lot of similarities, but there are key areas where one bike excels over the other. So, if you're looking to narrow down your options to one of these bikes as soon as possible, this guide will help steer you in the right direction.


Honda Grom Specs

At the heart of the Grom is a 124.9cc air-cooled single four stroke engine with a bore x stoke of 52.4mm x 57.9mm. Delivering the engine's power to the rear wheel of the Grom is a 4-speed transmission. The Grom is more than an inch shorter in the seat than the Z125 with a 30-inch seat height. It would be really hard to tell unless you had the bikes lined up next to each other but the Grom has a wheel base of 47.2 inches which is more an inch longer than the Z125. Fuel storage on the Grom is handled by a 1.47 gallon gas tank. Just like the Z125, the Grom rolls around on a pair of 12 inch wheel, where they differ though is in tire size. The Grom's tires are a bit chunkier with a 120/70-12 up front and a 130/70-12 rear. At the front of the bike you'll find suspension is handled by a 31mm inverted fork setup that offers 3.9 inches of travel while out back is a single shock with 4.1 inches of travel. Combine all these specs together and the Grom's curb weight comes to 229 pounds.

Kawasaki Z125 Pro Specs

Black Kawasaki Z125 Pro

Not quite as prominently shown as the engine on the Grom, but the Z125 Pro is also sports an air-cooled powerplant. If you were to tear the engine apart and do some measurements you'd find that Z125's piston stroke is slightly shorter than the Grom. The Z125 has stroke of 50.6mm but moves in a wider bore, 56.0mm, compared to the Grom. If you're on the taller side or have a longer inseam you'll appreciate the fact that the Z125 has a 31.7 inch seat height. Being 1 inch taller than the Grom might not sound like a lot but cam make a big difference for long rides or shorter/taller riders. Even though the Z125 is taller the wheelbase is shorter and measures out to 46.3 inches. The Z125 sips fuel from a 2 gallon gas tank--more than a half gallon larger than the Grom. As mentioned above, both bikes have 12 inch wheels but the difference lies in the tires. Again you'd have to have the bikes right next to each other to notice but the Z125's tires are a little narrower as it sits on a 100/90-12 front and a 120/70-12 rear. Just like the Grom the Z125 comes with an inverted frontend, however the Z125's has a diameter of 30mm compared to the Grom's 31mm. Out back you'll find a single shock like that on the Grom. Coincidentally, the Z125 has the same suspension travel front and rear as the Grom. While there are some places where the Z125 is bigger than the Grom, such as fuel capacity and seat height, with a curb weight of 224.8 pounds the Z125 actually weighs about 4 pounds less than the Grom.

No matter how serious you are about bikes and the hardware they're carrying, one of the first things you'll notice about a motorcycle is how it looks. Both bikes feature lines similar to larger sport bikes but they have more of a standard street bike aesthetic with less body work than traditional sport bikes. The Grom has a lot of broad angles and a more robust appearance. The engine and exhaust are real focal points as they are both fully exposed. Staring at the Grom you'll notice that it has a more pronounced 2-up seat with a dished center section to keep the rider secured in the cockpit and the passenger section kicked up on a plateau. Another difference you'll see between the two bikes is that the Grom's information center is perched atop the headlight whereas the Grom's is less noticeable.

The Z125 is more aggressively styled with sharper angles, a few pointy bits, and much more aerodynamic lines. On the Z125 you'll find shrouds and a chin spoiler help make the engine less noticeable while the exhaust is tucked neatly under the frame with just the tip of the muffler sticking out under the footpeg. Unlike the stepped seat on the Grom, the Z125's seat follows a smooth profile that gently raises toward the rear. When looking at the front of the bike, the Z125's info gauge is melded into the top of the head light for a more streamlined look.

Despite not being the most powerful of bikes on the market, both are quick, easy to shift and fun to maneuver. Ergonomically the bike are setup nearly identical with the foot controls sitting around 19 inches down from the top of the seat pocket and the handlebars sporting a slight rise that puts an average riders about in line with the mid-section. Both bike sport an inverted frontend and single rear shock with the same amount of travel front and rear. The tires are where we see a slight difference. With the Z125's slightly narrower tire combination along with having a less trail than the Grom (2.7 inches vs 3.2 inches) you can expect slightly quicker and more responsive handling. In addition, the Z125 is 4 pounds lighter when fully topped off, and while that might not sound like a lot, with both bikes weighing less than 230 pounds, the weight savings helps the Z125 feel noticeably lighter and more nimble. On the other hand the Grom may feel a bit more stable and balanced to newer riders.

Both these bikes are great for taking trips around and across town. Even so, to ensure you don't run afoul of the law, it's important to consider the age of the rider and the legislations in place in the locale you plan to ride. Both bikes feature 4-speed transmissions, which isn't bad for an around-towner, local commuter, or weekend- mini racer. As far as MPG, riders can save a few dollars here by parking their cars and hopping on a bike. Men's Journal estimates the MPG for the Z125 in the 80s, which sounds great until you see Honda's fuel efficiency estimate for the Grom is 134 MPG.

Speed and Braking

Honda Grom Speed and Braking

Despite being heavier, most reviewers agree that the Grom is faster. The 2019 model especially puts out more power and torque, boasting numbers like 9.7 horsepower at 7000 RPM and 8 lb-ft at 5500 RPM. Top speed for the Honda Grom peaks at around 63 MPH depending on several factors like rider's weight and how level/flat the road is. Braking duties on the Grom are handled by a 220mm single disc and dual piston caliper on the front wheel and a single piston caliper gripping down on a 190mm rotor in the rear. If you want the added benefit of an updated braking system with ABS Honda offers an ABS model.

Kawasaki Z125 Pro Speed and Braking

The 2019 Z125 Pro only produces 8.3 horsepower at 7800 RPM, and 7.1 lb-ft at 6000 RPM. The max speed estimates we've seen for the Kawasaki is right in line with the Grom at about 63 MPH. The Z125 comes with a pair of single piston brake calipers, one for the front and one for the rear. The rear rotor comes in at 200mm and the rear is 184mm. Unlike the Grom there is no Kawasaki Z125 Pro with ABS.


Honda Grom Price

How much you can expect to pay for the Honda Grom and the Kawasaki Z125 will depend on a few things. To that end, here are a few questions you need to answer. Are you purchasing the newest model brand new or a used model? The MSRP for the 2019 Honda Grom is $3,399, with an extra $200 added for the ABS model.

Kawasaki Z125 Pro Price

The 2019 Kawasaki Z125 has an MSRP of $3,199. If you are purchasing a used bike you can expect a larger gap for older models as the Honda brand is well-known around the world for its resale value. Also, as the market leader in the field of mini-bikes, the demand for the Honda Groms will be greater, thus driving up the price in comparison to the Z125. This makes buying the Z125 more attractive. However, owning and one day selling the Grom becomes more attractive for the better resale price.

In summary, what are the real differences between these two very similar bikes? Some riders argue that the Grom's appearance is too square and box-like. Still, almost anyone agrees that the suspension on the Z125 puts the Honda Grom to shame in ride quality. Not to be outdone, the Grom makes a comeback with advantages over the Z125 in speed, braking system, and fuel efficiency. The Z125 then fights back with a lower list price.

At Chaparral Motorsports, we believe both bikes can satisfy the sweet tooth of anyone craving a sporty mini-bike for weekend-racing or getting around town. It just comes down to what features matter most to you. Ready to get your own mini-bike and the top-notch riding gear to go with it? Come see us or give us a call at (800) 841-2960.

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